This section provides background information related to the present disclosure which is not necessarily prior art.
There is increasing interest in the use of transformative fluids for a wide range of applications. A transformative liquid consists of particles suspended in a liquid medium. When an external force or electromagnetic field comes into contact with the liquid, its mechanical properties change. The use of transformative fluid for energy absorption and dissipation has been employed in the automotive industry for adaptive vehicle suspensions. However, the beneficial properties of transformative fluids have not been fully exploited in other energy absorbing needs because of the lack of means to encapsulate such a fluid in differing geometries, and particularly in three dimensional (3D) geometries. The ability to capture transformative fluids in a wide variety of components having widely differing 3D geometries would open the use of transformative fluids to a wide range of applications heretofore not possible in traditional manufacturing processes.
Specific work in this technology area is disclosed in the following documents: Deshmukh, S. S., & McKinley, G. H. (2006), Adaptive energy-absorbing materials using field-responsive fluid-impregnated cellular solids. Smart Materials and Structures, 16(1), 106-113. http://doi.org/10.1088/0964-1726/16/1/013; Lorang, D. J., Tanaka, D., Spadaccini, C. M., Rose, K. A., Cherepy, N. J., & Lewis, J. A. (2011), Photocurable Liquid Core-Fugitive Shell Printing of Optical Waveguides, Advanced Materials, 23(43), 5055-5058. http://doi.org/10.1002/adma.201102411; Leonowicz, M., & Kozlowska, J. (2014). Rheological Fluids as a Potential Component of Textile Products. Fibres Textiles in Eastern Europe, 1(103), 28-33; Krueger, H., Vaezi, M., & Yang, S. (2014), 3D Printing of Magnetorheological Elastomers (MREs) Smart Materials (pp. 213-218), Presented at the 1st International Conference on Progress in Additive Manufacturing, Singapore, Research Publishing Services. http://doi.org/10.3850/978-981-09-0446-3 088; Deshmukh, et al., Smart Mater. Struct. (2006) describes an adaptive energy absorbing material by soaking a sponge with magnetorheological (MR) fluid; Lorang, et al., Adv. Mater (2011) describes using a concentric nozzle to additively manufacture two materials simultaneously; Leonowicz, et al., FTEE (2014) describes how MR fluid could be integrated into protective textiles by placing bags of the fluid behind Kevlar, and how MR fluid can increase the bullet resistivity of Kevlar when placed behind it; Leonowicz, et al., FTEE (2014) describes integrating sheer thickening fluid (STF) into Kevlar by soaking the Kevlar in the STF, and shows that the bullet resistivity of Kevlar increased when soaked with STF, and that sharp objects had a harder time piercing Kevlar when soaked with STF; Krueger, et al., Pro-AM (2014) describes the use of a dual head 3D printer to print silicone and a dry powder. All of the foregoing documents are hereby incorporated by reference into the present disclosure.